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Its not a meme. For example, C has pointer provenance, so pointers arent just addresses. Thats why type punning is such a mess. If a lang claims to be super cl

Its not a meme. For example, C has pointer provenance, so pointers arent just addresses. Thats why type punning is such a mess. If a lang claims to be super close to the hardware this seems like a very weird thing.

1718627440 8mo ago
C is super close to the hardware in that it works exactly like the abstract C machine, which is kind of a generalization of the common subset of a lot of machines, invented to make it portable, i.e. viable to be implemented straightforwardly on various architectures. For example pointer provenance makes it work on machines with segmented storage, these can occur anywhere, so there is no guarantee that addresses beyond a single allocation are expressible or meaningful. What makes C feel free for programming is that instead of prescribing an implementation paradigm, it instead exposes a computing model and then lets the programmer write whatever is possible with that (and also what is not -- UB). And a lot of higher level abstractions are quickly implemented in C, e.g. inheritance and polymorphism, but then they still allow to be used in ways you like, so you can not just do pure class inheritance, but get creative with a vtable, or just use another vtable with the same object. These are things you can't do when the classes are a language construct.
- ghosty141 8mo ago
  The C abstract machine is exactly the important part. There is a difference between saying C is close to "the hardware" and C is close to the C abstract machine. The latter like you described has a few concepts that allow for abstraction and thus portability but obviously they lead to situations where the "maps to the hardware" doesn't seem to hold true. My gripe is only with people acting like the C abstract machine doesn't exist and C is just syntax sugar for a bit of assembly. It's a bit more involved than that.
  - rramadass 8mo ago
    > The C abstract machine is exactly the important part. ... My gripe is only with people acting like the C abstract machine doesn't exist and C is just syntax sugar for a bit of assembly. It's a bit more involved than that. Most people have no understanding of an abstract machine though the very idea of a high-level programming language is based on it. The C Language Standard itself specifies "Program Execution" only on a "Abstract Machine". Mapping that abstract machine to an ISA/Memory on real hardware is the task of the C compiler. It can do this in any manner as long as the observable behaviour of the program is "as-if" it ran on the abstract machine. Relevant quote: A conforming implementation executing a well-formed program shall produce the same observable behavior as one of the possible executions of the corresponding instance of the abstract machine with the same program and the same input. Further Resources; Wikipedia Abstract machine - https://en.wikipedia.org/wiki/Abstract_machine https://en.wikipedia.org/wiki/Abstract_machine Abstract machines for programming language implementation (pdf) - https://www.rw.cdl.uni-saarland.de/people/diehl/private/pubs/articleDiehlHartelSestoft.pdf https://www.rw.cdl.uni-saarland.de/people/diehl/private/pubs... The Abstract Machine: A Pattern for Designing Abstract Machines (pdf) - https://www.plopcon.org/pastplops/plop99/proceedings/garcia/garcia.pdf https://www.plopcon.org/pastplops/plop99/proceedings/garcia/...
direwolf20 8mo ago
It remains close to computer hardware + optimiser. This provenance thing was introduced to aid optimisation.

1718627440 8mo ago

C is super close to the hardware in that it works exactly like the abstract C machine, which is kind of a generalization of the common subset of a lot of machines, invented to make it portable, i.e. viable to be implemented straightforwardly on various architectures. For example pointer provenance makes it work on machines with segmented storage, these can occur anywhere, so there is no guarantee that addresses beyond a single allocation are expressible or meaningful. What makes C feel free for programming is that instead of prescribing an implementation paradigm, it instead exposes a computing model and then lets the programmer write whatever is possible with that (and also what is not -- UB). And a lot of higher level abstractions are quickly implemented in C, e.g. inheritance and polymorphism, but then they still allow to be used in ways you like, so you can not just do pure class inheritance, but get creative with a vtable, or just use another vtable with the same object. These are things you can't do when the classes are a language construct.

ghosty141 8mo ago
The C abstract machine is exactly the important part. There is a difference between saying C is close to "the hardware" and C is close to the C abstract machine. The latter like you described has a few concepts that allow for abstraction and thus portability but obviously they lead to situations where the "maps to the hardware" doesn't seem to hold true. My gripe is only with people acting like the C abstract machine doesn't exist and C is just syntax sugar for a bit of assembly. It's a bit more involved than that.
- rramadass 8mo ago
  > The C abstract machine is exactly the important part. ... My gripe is only with people acting like the C abstract machine doesn't exist and C is just syntax sugar for a bit of assembly. It's a bit more involved than that. Most people have no understanding of an abstract machine though the very idea of a high-level programming language is based on it. The C Language Standard itself specifies "Program Execution" only on a "Abstract Machine". Mapping that abstract machine to an ISA/Memory on real hardware is the task of the C compiler. It can do this in any manner as long as the observable behaviour of the program is "as-if" it ran on the abstract machine. Relevant quote: A conforming implementation executing a well-formed program shall produce the same observable behavior as one of the possible executions of the corresponding instance of the abstract machine with the same program and the same input. Further Resources; Wikipedia Abstract machine - https://en.wikipedia.org/wiki/Abstract_machine https://en.wikipedia.org/wiki/Abstract_machine Abstract machines for programming language implementation (pdf) - https://www.rw.cdl.uni-saarland.de/people/diehl/private/pubs/articleDiehlHartelSestoft.pdf https://www.rw.cdl.uni-saarland.de/people/diehl/private/pubs... The Abstract Machine: A Pattern for Designing Abstract Machines (pdf) - https://www.plopcon.org/pastplops/plop99/proceedings/garcia/garcia.pdf https://www.plopcon.org/pastplops/plop99/proceedings/garcia/...

direwolf20 8mo ago

It remains close to computer hardware + optimiser. This provenance thing was introduced to aid optimisation.